Field of the Disclosure
Aspects of the present invention generally relate to an image reading apparatus capable of reading both sides of a document, a control method for the image reading apparatus, and a storage medium.
Description of the Related Art
In recent years, there has been an increasing need for efficiently computerizing office documents, and a two-sided simultaneous reading system has become mainstream. In the two-sided simultaneous reading system, two reading units, one for a front side and the other for a back side, respectively, are provided in a document reading apparatus (automatic document feeder (ADF)). In such a document reading apparatus, these two reading units are provided over a document conveyance path to read the respective sides of a document, and both sides of the document are read without reversing a conveyance direction of the document. As a result, the time required for reading the two-sided document is reduced. Further, in the ADF of the two-sided simultaneous reading system, the reading unit for the back side is installed on the document conveyance path side of the ADF, and this installation is mainstream. This reading unit for the back side needs to be in an operational state at least when two-sided reading is performed. This reading unit for the back side is not necessarily energized when one-sided reading is performed. Therefore, some of the apparatuses are controlled to turn on and activate the reading unit for the back side upon being instructed by a user to execute two-sided reading, in order to reduce power consumption or increase the life of the unit.
In addition, in general, a reading sensor has reading characteristics that change due to an elapsed time or an environmental change such as a temperature rise after start of driving. For this reason, adjustment operation is performed before reading. The adjustment operation mainly includes offset adjustment, reading gain adjustment, and light amount adjustment, besides shading correction. For example, the adjustment operation is performed for each of the front side reading unit and the back side reading unit, after an instruction for starting a two-sided reading job is provided by a press of a start key by the user. In this process, the time required from the job start instruction to the reading start may be reduced, by starting the adjustment operation first for the reading unit for a side that is expected to consume a longer time for adjustment. A method for achieving such a reduction in time has been discussed in, for example, Japanese Patent Application Laid-Open No. 2008-22527.
However, the adjustment operation begins upon receipt of the instruction for starting the two-sided reading job from the user and thus, if this adjustment operation takes a long time, a waiting time before the start of reading processing increases. As a result, a waiting time before completion of reading also increases, thereby reducing convenience.